Liquid crystal display device

ABSTRACT

The liquid crystal display device of this invention includes: a plurality of pixels including right-eye pixels and left-eye pixels; a display screen constructed of the plurality of pixels; a first substrate including a first display electrode; a second substrate including a second display electrode arranged to oppose the first display electrode; a polarizing layer disposed in at least one of the first substrate and the second substrate; and a reflection film disposed in one of the first substrate and the second substrate, wherein the polarizing layer has first regions arranged to correspond to the right-eye pixels and second regions arranged to correspond to the left-eye pixels, the first regions selectively transmitting first polarized light while the second regions selectively transmitting second polarized light which is different from the first polarized light.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device capableof displaying stereoscopic three-dimensional images which is used for TVsets, game machines, personal computers, CAD apparatus, medicalmonitors, portable information terminals, and the like.

2. Description of the Related Art

It has been long attempted to reproduce stereoscopic images orthree-dimensional images. A variety of methods have been proposed torealize this goal, including a method using a laser hologram and thelike. Among these methods, two types of three-dimensional image displaymethods with higher perfection which can display full-color movingpictures of three principal colors have been proposed. These two typesare based on the same principle: That is, different images for the rightand left eyes of an observer are separately displayed, to generate theparallax between the two eyes by the image deviation between the twoeyes, and thus to provide the observer with the sense of depth in theimages.

The first one of the two methods is a polarizing glasses method. In thismethod, images for the right and left eyes include two types of linearlypolarized light in which polarizing directions are inclined at an angleof 90° from each other. The observer perceives three-dimensional imagesby wearing a pair of polarizing glasses. In the case of projectiondisplay, images for right and left eyes are superimposed with each otheron a screen using two polarizing projectors. In the case of direct-viewdisplay, images output from two display devices are synthesized by ahalf mirror or a polarizing mirror.

The second one of the two methods is a shutter glasses method. In thismethod, images for right and left eyes are displayed by a single displaydevice using time division. The observer wears a pair of glasses havinga shutter function which alternately opens and closes in synchronizationwith the displayed images so as to provide three-dimensional images.This method is applicable to both the projection display and thedirect-view display.

In the above two methods, images for right and left eyes are bothpresented as two-dimensional images. These two-dimensional images may bedisplayed by a liquid crystal display (LCD), cathode ray tube (CRT), aplasma display, or the like depending on the use of the images.

The polarizing glasses method requires two display devices and aprojection device since two images having different polarizing axes mustbe simultaneously displayed at any time. This increases the cost and thesize of the entire apparatus, and thus is not suitable for domestic use.

In order to overcome the above problem of the polarizing glasses method,Japanese Laid-Open Publication No. 58-184929, for example, proposes amethod for displaying three-dimensional images by use of a singledisplay device. According to this method, a mosaic polarizing layercomposed of a plurality of portions corresponding to pixels arranged ina mosaic shape where the polarizing axes of adjacent portions areperpendicular to each other is closely attached to the outer surface ofthe display device (CRT or LCD). The observer can perceivethree-dimensional images by observing two-dimensional images for theright and left eyes presented by the display device via a pair ofpolarizing glasses. The above publication, however, discloses nopractical description on the position of the mosaic polarizing layer inthe display device when the display device is an LCD. Hereinbelow,therefore, the method disclosed in the above publication will bedescribed assuming that the polarizing layer is disposed on the outersurface of a liquid crystal display device.

FIG. 13 is a conceptual view of a liquid crystal display device having athree-dimensional display function proposed in Japanese Laid-OpenPublication No. 58-184929 mentioned above.

A display device body 701 includes right-eye pixels 706 and left-eyepixels 707 for displaying images for the right and left eyes,respectively. The right-eye and left-eye pixels 706 and 707 constitute adisplay screen. Two types of polarizing layers 703 and 704 of whichpolarizing axes are perpendicular to each other are disposed alternatelyon the front side of the display screen. More specifically, thepolarizing layers 703 and 704 are disposed so as to correspond to theright-eye pixels 706 and the left-eye pixels 707, respectively, todistinguish images for the right eye and the left eye from each other.The observer wears a pair of polarizing glasses 712 which include aright-eye polarizing plate 712b of which polarizing axis is identical tothat of the polarizing layers 703 disposed in front of the right-eyepixels 706 and a left-eye polarizing plate 712a of which polarizing axisis identical to that of the polarizing layers 704 disposed in front ofthe left-eye pixels 707. By wearing the pair of glasses 712, the rightand left eyes of the observer observe only images for the right and lefteyes, respectively, and thus perceives stereoscopic three-dimensionalimages.

The display device body 701 includes a pair of glass substrates 702a and702b disposed to sandwich a liquid crystal layer 705 therebetween. Theright-eye pixels 706 and the left-eye pixels 707 are formed on thesurface of one of the glass substrates, i.e., the glass substrate 702a(located left as is viewed in FIG. 13), facing the liquid crystal layer705. An alignment film 710a is formed on the right-eye and left-eyepixels 706 and 707. A polarizing plate 708 is disposed on the surface ofthe glass substrate 702a opposite to the surface thereof facing theliquid crystal layer 705. A transparent electrode 709 and an alignmentfilm 710b are formed in this order on the surface of the other glasssubstrate, i.e., the glass substrate 702b, facing the liquid crystallayer 705. The liquid crystal layer 705 is sealed with a sealing member711 formed to surround the liquid crystal layer 705.

The conventional display device with the above configuration has thefollowing problem.

Referring to FIG. 14, in the display device body 701, the glasssubstrate 702b exists between the right-eye and left-eye pixels 706 and707 and the right-eye and left-eye polarizing layers 703 and 704. Whenthe observer observes the display screen from the front position as isshown by the dash-dot lines in FIG. 14, the observer can perceive normalthree-dimensional images. However, as the eyes of the observer moveupward or downward from the front position, the right-eye pixels 706 maybe observed via the polarizing layers 704 for the left eye and,reversely, the left-eye pixels 707 may be observed via the polarizinglayers 703 for the right eye, as is shown by the dotted lines in FIG.14. In such a case, a phenomenon called crosstalk may be generated inwhich some images for right and left eyes are observed by the reverseeyes, and thus actual three-dimensional images may not be obtained. InFIG. 14, some components of the display device body 701 shown in FIG. 13are omitted for simplification.

In order to eliminate such crosstalk, Japanese Laid-Open Publication No.62-135810 proposes a display device including a single transparentliquid crystal display element. In this proposed display device,polarizing layers in which the polarizing directions are different fromeach other are disposed inside a pair of glass substrates of thetransparent liquid crystal display element. With this configuration,right-eye pixels and left-eye pixels of the transparent liquid crystaldisplay element are adjacent to the polarizing layers for the right eyeand the polarizing layers for the left eye, respectively. This preventsthe generation of crosstalk as described above even when the eyes of theobserver move upward or downward from the front position of the displayscreen. As a result, the range within which three-dimensional images canbe perceived is not limited, and thus a display device capable ofdisplaying three-dimensional images with a wide viewing angle can beobtained.

A transmission liquid crystal display element is conventionally used forsuch a liquid crystal display device which has the three-dimensionaldisplay function and employs the polarizing glasses method. This type ofdevice requires a light source for illuminating the liquid crystaldisplay element, i.e., a backlight, increasing power consumption. In theapplications using a battery, such as portable information terminals,this light source requirement shortens the time duration available fromone charging of a battery. Providing a light source also increases theproduction cost of the display device.

In view of the foregoing, the objective of the present invention is toprovide a thin and light-weight liquid crystal display device with thethree-dimensional display function which has a prolonged time durationwith reduced power consumption, can be manufactured at low cost, andeliminates the generation of crosstalk at the display ofthree-dimensional images to realize good image display with a wideviewing angle and thus to expand the applicable field of view of thedevice.

SUMMARY OF THE INVENTION

The liquid crystal display device of this invention includes: aplurality of pixels including right-eye pixels and left-eye pixels; adisplay screen constructed of the plurality of pixels; a first substrateincluding a first display electrode; a second substrate including asecond display electrode arranged to oppose the first display electrode;a polarizing layer disposed in at least one of the first substrate andthe second substrate; and a reflection film disposed in one of the firstsubstrate and the second substrate, wherein the polarizing layer hasfirst regions arranged to correspond to the right-eye pixels and secondregions arranged to correspond to the left-eye pixels, the first regionsselectively transmitting first polarized light while the second regionsselectively transmitting second polarized light which is different fromthe first polarized light.

In one embodiment of the invention, the polarizing layer is disposed inthe second substrate, and the first display electrode is a reflectivedisplay electrode which also serves as a reflection film.

In another embodiment of the invention, the first polarized light andthe second polarized light are linearly polarized light of whichpolarizing directions are perpendicular to each other.

In still another embodiment of the invention, the first polarized lightand the second polarized light are circularly polarized light of whichpolarizing directions are rotated in opposite directions to each other.

In still another embodiment of the invention, the liquid crystal displayfurther includes an optical rotation layer or a phase layer disposed tocorrespond to at least either of the right-eye pixels and the left-eyepixels.

In still another embodiment of the invention, the first substratefurther includes switching elements connected to the first displayelectrode and signal lines connected to the switching elements.

In still another embodiment of the invention, the first substratefurther includes switching elements connected to the first displayelectrode, signal lines connected to the switching elements, and aninterlayer insulating film formed over the switching elements and thesignal lines, and the first display electrode is formed on theinterlayer insulating film to cover the switching elements.

In still another embodiment of the invention, the liquid crystal displaydevice further includes a liquid crystal layer interposed between thefirst substrate and the second substrate, and one of an electric fieldcontrol birefringence mode, a guest-host mode, and a twisted nematicmode is employed as a display mode.

In still another embodiment of the invention, the liquid crystal displaydevice further includes a liquid crystal layer interposed between thefirst substrate and the second substrate and alignment films disposed inthe first substrate and the second substrate, wherein the alignmentfilms are alignment-treated so that liquid crystal molecules in regionsof the liquid crystal layer corresponding to the right-eye pixels andliquid crystal molecules in regions of the liquid crystal layercorresponding to the left-eye pixels are oriented in directionsperpendicular to each other.

In still another embodiment of the invention, the first substrateincludes a first insulating plate and the second substrate includes asecond insulating plate, and the polarizing layer is located between thefirst insulating plate and the second insulating plate.

Alternatively, the liquid crystal display device according to thepresent invention includes: a plurality of pixels including right-eyepixels and left-eye pixels; a display screen constructed of theplurality of pixels; a main substrate; and a counter substrate, whereinthe main substrate includes switching elements, signal lines, aninterlayer insulating film formed over the switching elements and thesignal lines, and pixel electrodes formed on the interlayer insulatingfilm, the counter substrate includes a light reflection layer, and acounter electrode disposed so as to oppose the pixel electrodes, and theinterlayer insulating film has first regions arranged to correspond tothe right-eye pixels and second regions arranged to correspond to theleft-eye pixels, the first regions selectively transmitting firstpolarized light while the second regions selectively transmitting secondpolarized light which is different from the first polarized light.

In one embodiment of the invention, the interlayer insulating filmincludes a polarizing layer and a phase layer, the polarizing layerselectively transmits the first polarized light in the first regions andthe second polarized light in the second regions, and the phase layerhas a phase difference function only in the first regions.

In another embodiment of the invention, the liquid crystal displaydevice further includes a liquid crystal layer interposed between themain substrate and the counter substrate, wherein the first polarizedlight which has passed through the polarizing layer is provided with aphase difference by the phase layer to become the second polarizedlight, and thus the second polarized light is incident on the liquidcrystal layer over the entire display screen.

In still another embodiment of the invention, the liquid crystal displaydevice further includes a liquid crystal layer interposed between themain substrate and the counter substrate, wherein the liquid crystallayer includes first liquid crystal regions corresponding to theright-eye pixels and second liquid crystal regions corresponding To theleft-eye pixels, and liquid crystal molecules in the first liquidcrystal regions are oriented to selectively optically modulate the firstpolarized light, while liquid crystal molecules in the second liquidcrystal regions are oriented to selectively optically modulate thesecond polarized light.

In still another embodiment of the invention, the plurality of pixelsinclude a plurality of pixel groups, each of the plurality of pixelgroups being composed of at least one pixel for displaying a same image,and the plurality of pixel groups are arranged so that right-eye pixelgroups and left-eye pixel groups are adjacent to each other.

In still another embodiment of the invention, the plurality of pixelsare arranged in a matrix, and each of the plurality of pixel groups iscomposed of one row of pixels aligned in a horizontal direction or onecolumn of pixels aligned in a vertical direction.

Alternatively, the liquid crystal display device according to thepresent invention includes: a plurality of pixels including right-eyepixels and left-eye pixels; a display screen constructed of theplurality of pixels; a main substrate; a counter substrate; and a liquidcrystal layer interposed between the main substrate and the countersubstrate, wherein the main substrate includes switching elements,signal lines, an interlayer insulating film formed over the switchingelements and the signal lines, and pixel electrodes formed on theinterlayer insulating film, the counter substrate includes a lightreflection layer, and a counter electrode disposed so as to oppose thepixel electrodes, the interlayer insulating film has first regionsarranged to correspond to the right-eye pixels and second regionsarranged to correspond to the left-eye pixels, the first regionsselectively transmitting first polarized light while the second regionsselectively transmitting second polarized light which is different fromthe first polarized light, and the liquid crystal layer modulates atransmission amount of at least one of the first polarized light and thesecond polarized light incident on the liquid crystal layer from theinterlayer insulating film.

In one embodiment of the invention, the plurality of pixels include aplurality of pixel groups, each of the plurality of pixel groups beingcomposed of at least one pixel for displaying a same image, and theplurality of pixel groups are arranged so that right-eye pixel groupsand left-eye pixel groups are adjacent to each other.

In another embodiment of the invention, the plurality of pixels arearranged in a matrix, and each of the plurality of pixel groups iscomposed of one row of pixels aligned in a horizontal direction or onecolumn of pixels aligned in a vertical direction.

In still another embodiment of the invention, the liquid crystal displaydevice further includes a liquid crystal layer interposed between themain substrate and the counter substrate, wherein the interlayerinsulating film includes a phase layer and a polarizing layer, thepolarizing layer being disposed closer to the liquid crystal layer thanthe phase layer, the first polarized light and the second polarizedlight are linearly polarized light, and the phase layer converts thefirst linearly polarized light received from the polarizing layer intofirst circularly polarized light in the first region, and converts thesecond linearly polarized light received from the polarizing layer intosecond circularly polarized light in the second region.

It has been conventionally impossible to form a polarizing layer in theinner portion of one of a pair of substrates constituting a liquidcrystal display device which includes switching elements such as TFTsand the like (called an active matrix substrate) because no polarizationselectable material durable for the process temperature at thefabrication of the TFTs is available. According to the presentinvention, the formation of a polarizing layer in the inner portion ofthe active matrix substrate is realized by providing an interlayerinsulating film formed in the inner surface portion of the active matrixsubstrate with the polarization selection function. This solves theconventional problems that the polarizing layer loses the polarizationselection function and that crosstalk is generated at the display ofthree-dimensional images. As a result, images with a wide viewing anglecan be obtained, and the display quality improves.

Since the interlayer insulating film is provided with the polarizationselection function, it is not necessary to form a separate polarizinglayer in the inner portion of the active matrix substrate. This aspectof the invention shortens the fabrication process.

According to the present invention, three-dimensional images aredisplayed by a liquid crystal display device of a reflective type. Alight source for illumination is therefore unnecessary unlike the caseof a liquid crystal display device of a transmission type. Thereflective liquid crystal display device according to the presentinvention is therefore thin and light in weight, and reduces powerconsumption. Accordingly, the applicable field of such a display devicecapable of displaying three-dimensional images expands.

Thus, the invention described herein makes possible the advantage ofproviding a thin and light-weight liquid crystal display device with athree-dimensional display function which has a prolonged time durationwith reduced power consumption, can be manufactured at low cost, andeliminates the generation of crosstalk in three-dimensional imagedisplay to realize a good image display with a wide viewing angle andthus to expand the applicable field of the device.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a reflective liquid crystal display deviceof Example 1 according to the present invention.

FIG. 2 is a plan view of one pixel of an active matrix substrate of thereflective liquid crystal display device of FIG. 1.

FIG. 3 is a sectional view of the active matrix substrate, taken alongline A-A' of FIG. 2.

FIG. 4 is a sectional view of a reflective liquid crystal display deviceof Example 2 according to the present invention.

FIG. 5 is a sectional view of an alternative configuration of a countersubstrate of the reflective liquid crystal display device of Example 2.

FIG. 6 is a sectional view of a reflective liquid crystal display deviceof Example 3 according to the present invention.

FIG. 7 is a sectional view of one pixel of an active matrix substrate ofthe reflective liquid crystal display device of FIG. 6.

FIG. 8 is a sectional view of a reflective liquid crystal display deviceof Example 4 according to the present invention.

FIG. 9 is a sectional view of a reflective liquid crystal display deviceof Example 5 according to the present invention.

FIG. 10 shows an optical arrangement of the reflective liquid crystaldisplay device of FIG. 9.

FIGS. 11A and 11B illustrate the operational principle of the reflectiveliquid crystal display device of FIG. 9 when no voltage is applied andwhen a voltage is applied, respectively.

FIG. 12 is a sectional view of a reflective liquid crystal displaydevice of Example 6 according to the present invention.

FIG. 13 is a conceptual view of a conventional liquid crystal displaydevice with a three-dimensional display function using a pair ofpolarizing glasses.

FIG. 14 illustrates the generation of crosstalk in the conventionalliquid crystal display device of FIG. 13.

FIG. 15 is a sectional view of an alternative example of the reflectiveliquid crystal display device of Example 4 according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described by way of examples withreference to the accompanying drawings.

EXAMPLE 1

In Example 1, a light reflection layer is disposed in the outer surfaceportion of one of a pair of substrates constituting a part of a liquidcrystal display device, i.e., a counter substrate, and polarizing layersand a phase layer are disposed in the inner surface portion of the othersubstrate, i.e., an active matrix substrate, so as to form a reflectiveliquid crystal display device. Two types of light having differentpolarizing states corresponding to right-eye and left-eye pixels areoutput from the side of the active matrix substrate. In this example,pixels of the liquid crystal display device are divided into a pluralityof groups each including at least one pixel. Pixels in the same groupare used to display the same image.

FIG. 1 is a sectional view schematically showing a reflective liquidcrystal display device 100 of Example 1 according to the presentinvention.

The reflective liquid crystal display device 100 includes an activematrix substrate 101, a counter substrate 102, and a liquid crystallayer 103 interposed between the substrates 101 and 102. The activematrix substrate 101 includes a transparent insulating substrate 101a.Gate signal lines 104 and then a gate insulating film 105 are formed onthe inner surface of the transparent insulating substrate 101a facingthe liquid crystal layer 103 as shown in FIG. 1. Thin film transistors(TFTs) as switching elements, signal lines, and the like are formed onthe gate insulating film 105 though they are not shown. Polarizinglayers 106 and 107 and a phase plate 108 which also serve as aninterlayer insulating film are disposed on the resultant substrate.

The polarizing layers 106 and 107 have polarizing axes 106a and 107a,respectively, which are perpendicular to each other, and are disposed sothat one of each pair of the polarizing layers 106 and 107 correspondsto a right-eye pixel group while the other one corresponds to a left-eyepixel group. In this example, each pixel group is composed of one row ofpixels aligned in the horizontal direction (i.e., pixels sharing a samegate signal line), and such rows of pixel groups are alternatelyallocated for the right eye and the left eye every row. Therefore, thepolarizing layers 106 and 107 are also alternately disposed in every rowof pixels.

The phase layer 108 is composed of regions 109 which do not provide aphase difference to incident light and regions 110 which provide a phasedifference to incident light. The regions 109 and 110 are arranged tocorrespond to the polarizing layers 106 and 107, respectively, as shownin FIG. 1. Thus, the regions 109 and 110 are also alternately arrangedevery row of pixels. The regions 110 having the phase differenceproviding function have an optical axis shifted by 45° with respect tothe polarizing axis 107a of the corresponding polarizing layers 107,thereby to provide a phase difference of a half wavelength.

A plurality of transparent electrodes 112 and an alignment film 113a forregulating the orientation of liquid crystal molecules in the liquidcrystal layer 103 are disposed in this order on the phase layer 108.

The counter substrate 102 includes a transparent insulating substrate102a. Color filters 120, a counter electrode 122, and an alignment film113b are formed in this order on the transparent insulating substrate102a. The color filters 120 may be made of red (R), green (G), and blue(B) pixels, or made of cyan (C), magenta (M), and yellow (Y) pixels, inconsideration of the image display by the reflective display device anddepending on the field where the display device is applied.

A light reflection layer 124 made of a metal such as Al or Ag is formedon the outer surface of the transparent insulating substrate 102a of thecounter substrate 102. A reflection blocking layer 111 is formed on theouter surface of the transparent insulating substrate 110a of the activematrix substrate 101 for preventing ambient light from reflecting fromthe insulating substrate 101a. Thus, in the reflective liquid crystaldisplay device 100 of this example, light is incident on the side ofactive matrix substrate 101, reflected by the light reflection layer 124in the outer surface of the counter substrate 102 after passing throughthe liquid crystal layer 103, and output from the active matrixsubstrate 101 after passing again through the liquid crystal layer 103.

The liquid crystal layer 103 is made of a guest-host mode liquid crystalmaterial. In this example, a mixture of a p-type black pigment as adichromatic pigment and a nematic liquid crystal material having apositive dielectric anisotropy is used. The liquid crystal molecules andthe dichromatic pigment molecules are aligned so that the opticalabsorption axis of the dichromatic pigment molecules obtained when theliquid crystal molecules and the dichromatic pigment molecules arealigned is parallel to the polarizing direction of light which haspassed through the polarizing layers and the phase layer. With thisalignment, polarized light incident on the liquid crystal layer 103 isabsorbed by the dichromatic pigment molecules when the TFTs (not shown)are in the OFF state, i.e., when no electric field is applied to theliquid crystal layer 103, resulting in a black display. When the TFTsare in the ON state, i.e., when an electric field is applied to theliquid crystal layer 103, the orientation directions of the liquidcrystal molecules and the dichromatic pigment molecules change.Polarized light incident on the liquid crystal layer 103 thereforepasses through the liquid crystal layer 103 without being absorbed bythe dichromatic pigment molecules.

Next, an exemplified method for fabricating the active matrix substrate101 in this example will be described with reference to FIGS. 1 to 3.FIG. 2 is a plan view of the active matrix substrate 101, and FIG. 3 isa sectional view taken along line III--III of FIG. 2. FIGS. 2 and 3 showonly a portion corresponding to one pixel of the active matrix substratefor simplification.

A metal such as Ta or Al is deposited on the transparent insulatingsubstrate 101a by sputtering and patterned to form the gate signal lines104. The gate signal lines 104 include branches used as gate electrodesof TFTs 114 of respective pixels. Electrodes 117 of storage capacitorsto be disposed in parallel with the gate signal lines 104 may also beformed together with the gate signal lines 104. The gate insulating film105 is then formed over the entire surface of the transparent insulatingsubstrate 101a covering the gate signal lines 104. SiN or SiO₂ may beused for the gate insulating film 105.

Semiconductor layers 130 are then formed on the gate insulating film 105and patterned into a predetermined shape. Channel protection layers 131made of SiN, for example, are formed on the portions of thesemiconductor layers 130 located above the gate electrodes. Thereafter,an n⁺ Si layer is formed on the resultant substrate and patterned toform source electrodes 132a and drain electrodes 132b which cover bothside portions of the channel protection layers 131 and part of thesemiconductor layers 130. Each pair of the source electrode 132a and thedrain electrode 132b are therefore separated from each other at the topof the corresponding channel protection layer 131.

Source signal lines 116 are then formed. In this example, as shown inFIG. 3, each source signal line 116 has a double-layer structurecomposed of a lower line 116a made of a transparent conductive materialsuch as ITO and an upper line 116b made of a metal material such as Taor Al. The source signal lines 116 are in contact with side portions ofthe source electrodes 132a. Simultaneously with the formation of thesource signal lines 116, transparent conductive films 118a and metalfilms 118b are formed so that they are in contact with side portions ofthe drain electrodes 132b. Each transparent conductive film 118a extendsto connect the drain electrode 132b with the corresponding pixelelectrode 112 and also serves as an electrode 119 of the storagecapacitor.

The polarizing layers 106 and 107 and the phase layers 108 are formed onthe transparent insulating substrate 101a with the above layers formedthereon. The polarizing layers 106 and 107 of which polarizing axes aredifferent from each other are formed by the same process. That is, amixture of a photo-oriented organic material and a dichromatic pigmentdye or iodide is applied to the resultant surface of the transparentinsulating substrate 101a to a predetermined thickness. The appliedmaterial is then irradiated with ultraviolet (UV) light includinglinearly polarized light via a mask disposed on the applied material.The mask has open portions each corresponding to one row of pixels andlight-shading portions each corresponding to one row of pixels and theseportions are alternately arranged. The UV light passes through the openportions of the mask to form the polarizing layers of which polarizingaxis is along the polarizing axis of the irradiated UV light. Then, themask is rearranged so that the open portions are located above theportions of the applied material which have not been irradiated with theUV light, and these are irradiated with UV light including linearlypolarized light of which polarizing axis is different from that of thepreviously-used UV light. In this way, polarizing layers of whichpolarizing axis is different from that of the previously-formedpolarizing layers are formed. A polymer material which exhibitsphotoisomerization reaction (e.g., a polymer including azobenzene as aside chain) as disclosed in Japanese Laid-Open Publication No. 7-261024and a dichromatic pigment may be used for the polarizing layers.

The phase layer 108 is formed in substantially the same procedure as thepolarizing layers 106 and 107. That is, a photopolymerizable liquidcrystal material, for example, is applied to the transparent insulatingsubstrate 101a with the polarizing layers 106 and 107 formed thereon.The applied material is irradiated with UV light including linearlypolarized light via a mask with a pattern as described above. As aresult, regions of the applied material irradiated with the UV lightconstitute the regions 110 which have an optical axis along thepolarizing axis of the irradiated linearly polarized light and provide ahalf-wavelength phase difference. A UV-curable liquid crystal materialexhibiting the nematic phase at room temperature as disclosed inJapanese Laid-Open Publication No. 8-29618 may be used for the phaselayer.

The thus-formed polarizing layers 106 and 107 and the phase layers 108also serve as the interlayer insulating film. Contact holes 134 areformed through the polarizing layers 106 and 107 and the phase layer 108to reach respective connection electrodes 118 by photolithography, forexample, as shown in FIG. 3.

The pixel electrodes 112 made of transparent conductive films are thenformed on the phase layer 108. Since the polarizing layers 106 and 107and the phase layer 108 serve as the interlayer insulating film, theelectrodes 112 can be formed to overlap the gate signal lines 104, thesource signal lines 116, and the TFTs 114. Each pixel electrode 112 isconnected with the connection electrode 118 which is in turn connectedwith the drain electrode 132b of the TFT 114 via the contact hole 134.

Finally, the alignment film 113a is formed to cover the pixel electrodes112, and the reflection blocking layer 111 composed of a single-layer ormulti-layer film of a dielectric such as MgF₂ is formed on the surfaceof the transparent insulating substrate 101a opposite to the surfacethereof where the pixel electrodes 112 and the like are formed. Thus,the active matrix substrate 101 is completed. The thus-obtained activematrix substrate 101 is attached together with the counter substrate 102so that the alignment films 113a and 113b face each other. A guest-hostmode liquid crystal material is injected in the space formed between thesubstrates 101 and 102 to form the liquid crystal layer 103.

According to the reflective liquid crystal display device 100 of Example1, ambient light is incident on the active matrix substrate 101, andconverted into two types of linearly polarized light of which polarizingaxes are perpendicular to each other by passing through the polarizinglayers 106 and 107 formed alternately every row of pixels. Then, thepolarizing axes of the two types of light become the same after passingthrough the phase layer 108. The thus-transformed light then reaches theliquid crystal layer 103 under the above state. Thus, the lighttransmittance amount can be adjusted for the entire screen bycontrolling the orientation directions of the liquid crystal moleculesand the dichromatic pigment molecules in the liquid crystal layer 103.More specifically, when the TFTs 114 (see FIGS. 2 and 3) are in the OFFstate, light is absorbed and thus a black display is obtained. On thecontrary, when the TFTs 114 are in the ON state, light passes throughthe liquid crystal layer 103 and the counter electrode 122 and the colorfilters 120 of the counter substrate 102 in this order to reach thelight reflection layer 124.

The light is then reflected by the light reflection layer 124 andincident again on the phase layer 108 via the reverse optical path whilethe polarizing direction is kept unchanged. Part of the light which isincident on the regions 110 of the phase layer 108 having the phasedifference providing function is provided with a half-wavelength phasedifference, to become light in which the polarizing direction is rotatedby 90°. As a result, two types of linearly polarized light in which thepolarization axes are perpendicular to each other are output from thephase layer 108 alternately every row of pixels. The polarizing layers106 and 107 thus receive light in which the polarization axes areidentical to their own polarization axes. Thus, the active matrixsubstrate 101 outputs light corresponding to right-eye images and lightcorresponding to left-eye images as two types of light in which thepolarizing axes are perpendicular to each other.

As described above, the reflective liquid crystal display device 100 ofExample 1 outputs light for right-eye images and light for left-eyeimages alternately every row of pixels. The observer can perceivethree-dimensional images output from the output side of the activematrix substrate 101 by wearing a pair of polarizing glasses (not shown)which includes polarizing plates having the polarizing axescorresponding to the polarizing axes of the polarizing layers 106 and107. When the observer does not wear the pair of polarizing glasses, heor she observes two-dimensional images.

The liquid crystal display device 100 of Example 1 which is of areflective type using ambient light requires no light source forillumination (backlight). Therefore, a three-dimensional image displaydevice with reduced power consumption is realized, allowing thethree-dimensional image display device to be used for a wider range ofapplications including apparatus driven with a battery.

Moreover, in the reflective liquid crystal display device 100 of Example1, the interlayer insulating film formed in the inner portion of theactive matrix substrate 101 for insulating the signal lines, the TFTs,and the like from the pixel electrodes is provided with at least one ofthe polarization selection function and the phase difference providingfunction. This reduces the number of steps and the number of componentsin the entire fabrication process of the liquid crystal display device.

EXAMPLE 2

In Example 2, a light reflection layer is disposed on the inner surfaceof the transparent insulating substrate of the counter substrate, andpolarizing layers are disposed on the inner surface of the transparentinsulating substrate of the active matrix substrate. A reflective liquidcrystal display device 200 of Example 2 will be described with referenceto FIGS. 4 and 5, where the same components as those shown in FIGS. 1 to3 are denoted by the same reference numerals, and the descriptionthereof is omitted here.

FIG. 4 is a sectional view schematically showing the reflective liquidcrystal display device 200 of Example 2 according to the presentinvention.

The reflective liquid crystal display device 200 includes an activematrix substrate 201, a counter substrate 202, and a liquid crystallayer 203 interposed between the substrates 201 and 202. The activematrix substrate 201 includes a transparent insulating substrate 101a.Gate signal lines 104 and then a gate insulating film 105 are formed onthe inner surface of the transparent insulating substrate 101a facingthe liquid crystal layer 203 as shown in FIG. 4. TFTs as switchingelements, signal lines, and the like are formed on the gate insulatingfilm 105 though they are not shown. Polarizing layers 106 and 107 and aphase plate 108 which also serve as an interlayer insulating film aredisposed on the resultant substrate.

The polarizing layers 106 and 107 have polarizing axes 106a and 107a,respectively, which are perpendicular to each other, and are disposed sothat one of each pair of the polarizing layers 106 or 107 corresponds toa right-eye pixel group while the other one corresponds to a left-eyepixel group. In this example, each pixel group is composed of one row ofpixels aligned in the horizontal direction (i.e., pixels sharing a samegate signal line). The polarizing layers 106 and 107 are thereforealternately disposed in every row of pixels. The phase layer 108 iscomposed of regions 109 which do not provide a phase difference toincident light and regions 110 which provide a phase difference toincident light. The regions 109 and 110 are arranged to correspond tothe polarizing layers 106 and 107, respectively, as shown in FIG. 4. Aplurality of transparent electrodes 112 as pixel electrodes are formedon the phase layer 108. The polarizing layers 106 and 107 are formed inthe manner described in Example 1.

An alignment film 213 is formed over the pixel electrodes 112. Thealignment film 213 is composed of regions 213a and 213b which arealternately arranged in every row of pixels as shown in FIG. 4. Theregions 213a and 213b of the alignment film 213 have beenalignment-treated so that the orientation direction of liquid crystalmolecules in contact with the regions 213a is different by 90° from thatof liquid crystal molecules in contact with the regions 213b. Areflection blocking film 111 is formed on the outer surface of thetransparent insulating substrate 101a of the active matrix substrate 201as in Example 1.

The counter substrate 202 includes a transparent insulating substrate102a. A light reflection layer 224, color filters 120, and a counterelectrode 122 are formed in this order on the transparent insulatingsubstrate 102a. The light reflection layer 224 is made of a metal suchas Al or Ag, for example. The color filters 120 may be made of red (R),green (G), and blue (B) pixels, or made of cyan (C), magenta (M), andyellow (Y) pixels, in consideration of the image display by thereflective display device and depending on the field where the displaydevice is applied.

An alignment film 214 having regions 214a and 214b which have beendifferently alignment-treated is formed on the counter electrode 122.The regions 214a and 214b of the alignment film 214 have beenalignment-treated so that the orientation direction of liquid crystalmolecules in contact with the regions 214a is different by 90° from thatof liquid crystal molecules in contact with the regions 214b. Theregions 214a and 214b are arranged alternately every row of pixel so asto face the regions 213a and 213b of the alignment film 213,respectively.

The liquid crystal layer 203 is made of a guest-host mode liquid crystalmaterial. In this example, a mixture of a p-type black pigment as adichromatic pigment and a nematic liquid crystal material having apositive dielectric anisotropy is used as in Example 1. The orientationdirection of liquid crystal molecules 203a in the portions of the liquidcrystal layer 203 interposed between the regions 213a of the alignmentfilm 213 and the regions 214a of the alignment film 214 is regulated bythe regions 213a and 214a. Likewise, the orientation direction of liquidcrystal molecules 203b in the portions of the liquid crystal layer 203interposed between the regions 213b of the alignment film 213 and theregions 214b of the alignment film 214 is regulated by the regions 213band 214b. Therefore, the orientation direction of the liquid crystalmolecules 203a is perpendicular to that of the liquid crystal molecules203b, and thus the two types of regions of the liquid crystal layer 203having the orientation directions perpendicular to each other are formedalternately in every row of pixels over the entire display screen. As aresult, the polarizing axis of light which has been incident on theactive matrix substrate 201 and has passed through the polarizing layers106 and 107 when no electric field is applied to the liquid crystallayer 203 is parallel to the optical absorption axis of dichromaticpigment molecules over the entire display screen. Black display istherefore obtained when TFTs (not shown) are in the OFF state. When theTFTs are in the ON state, light which has reached the liquid crystallayer 203 via the polarizing layers 106 and 107 is not absorbed by thedichromatic pigment molecules. The light is thus allowed to pass throughthe liquid crystal layer 203.

A photo-orientation method was used as an alignment treatment method forthe alignment films 213 and 214. That is, an alignment material such asa photosensitive resin, e.g., polyvinyl cinnamate, is applied to thetransparent insulating substrate 101a of the active matrix substrate 201and the transparent insulating substrate 102a of the counter substrate202 to a predetermined thickness. The applied material is thenirradiated with ultraviolet (UV) light including linearly polarizedlight in vertical and inclined directions via a mask disposed on theapplied material. The mask has open portions each corresponding to onerow of pixels and light-shading portions each corresponding to one rowof pixels alternately arranged. Thus, the regions 213a, 213b, 214a, and214b having alignment directions along the polarizing axes of theirradiated light are formed.

In the reflective liquid crystal display device 200 with the aboveconfiguration, ambient light is incident on the active matrix substrate201, and converted into two types of linearly polarized light of whichpolarizing axes are perpendicular to each other by passing through thepolarizing layers 106 and 107 formed alternately every row of pixels.The two types of light then pass through the alignment film 213 to reachthe liquid crystal layer 203. The orientation directions of the liquidcrystal molecules in the liquid crystal layer 203 are different by 90°every row of pixels in correspondence with the polarizing axes of thepolarizing layers 106 and 107. Accordingly, the amount of light passingthrough the liquid crystal layer 203 can be adjusted for the entirescreen by controlling the orientation directions of the liquid crystalmolecules and the dichromatic pigment molecules. More specifically, whenthe TFTs are in the OFF state, light is absorbed and thus black displayis obtained. On the contrary, when the TFTs are in the ON state, lightpasses through the liquid crystal layer 203, the alignment film 214, thecounter electrode 122, and the color filters 120 in this order to reachthe light reflection layer 224.

The light is then reflected by the light reflection layer 224 andincident again on the polarizing layers 106 and 107 via the reverseoptical path while keeping the polarizing directions unchanged. Thepolarizing layers 106 and 107 thus receive light of which polarizingaxes are identical to their own polarizing axes, and allow the receivedlight to pass therethrough and to be output from the active matrixsubstrate 201. Thus, light corresponding to right-eye images and lightcorresponding to left-eye images are output as two types of light ofwhich polarizing axes are perpendicular to each other.

With the liquid crystal display device 200 with the above configuration,the observer can perceive three-dimensional images output from the sideof the active matrix substrate 201 by wearing a pair of polarizingglasses (not shown) which includes polarizing plates having thepolarizing axes corresponding to the polarizing axes of the polarizinglayers 106 and 107. When the observer does not wear the pair ofpolarizing glasses, he or she observes two-dimensional images.

The liquid crystal display device 200 of Example 2 which is of areflective type using ambient light requires no light source forillumination (backlight).

Therefore, a three-dimensional image display device with reduced powerconsumption is realized, allowing the three-dimensional image displaydevice to be used for a wider range of applications including apparatusdriven with a battery.

Moreover, in the reflective liquid crystal display device 200 of Example2, the light reflection layer 224 is formed on the inner surface of thetransparent insulating substrate 102a. This eliminates the occurrence ofblur of pixel outlines caused by shadows of pixels due to the thicknessof the transparent insulating substrate 102a, and thus good displayquality can be obtained.

In Examples 1 and 2, the reflective liquid crystal display devices forcolor image display were described. The present invention is alsoapplicable to reflective liquid crystal display devices formonochromatic display. In the latter case, as shown in FIG. 5, a countersubstrate 302 includes the transparent insulating substrate 102a and alight reflection layer 324 made of a metal such as Al which also servesas a counter electrode. The alignment film is omitted in FIG. 5.

The display mode of the liquid crystal layer is not restricted to theguest-host mode as described above. The present invention is alsoapplicable to a liquid crystal display device of a reflective displaymode using polarizing plates, such as a reflective-optically compensatedbend (R-OCB) mode, a super-twisted nematic (STN) mode, a twisted nematic(TN) mode, and the like.

The present invention is not restricted to the configuration where thepolarizing layers and/or the phase layer are disposed in the activematrix substrate, i.e., the substrate where TFTs, lines, and the likeare formed. For example, when an STN-mode device where two polarizingplates are used to realize the reflective mode is used, polarizinglayers are also formed in the counter substrate, as well as in theactive matrix substrate, so that light which has passed throughtwo-stage polarizing layers is reflected by the light reflection layer.

In Examples 1 and 2, each pixel group is composed of one row of pixelsaligned in the horizontal direction. The present invention is notrestricted to this arrangement, but the same effect as that describedabove can be obtained when each pixel group is composed of one column ofpixels aligned in the vertical direction (i.e., pixels sharing a samesource signal line). In the latter case, the polarizing layers 106 and107, the regions 109 and 110 of the phase layer 108 without and with thephase difference providing function, respectively, the regions 213a and213b of the alignment film 213, and the regions 214a and 214b of thealignment film 214 are also alternately arranged every column of pixels.Alternatively, each pixel group may be composed of only one pixel, andright-eye pixels and left-eye pixels may be arranged in a checkered flagpattern. Each pixel group may also be composed of a plurality of rows ofpixels or a plurality of columns of pixels. In the latter case, however,the resolution is reduced compared with the case where each pixel groupis composed of one row of pixels or one column of pixels.

In Examples 1 and 2, two types of linearly polarized light of whichpolarizing directions are different from each other for the right-eyepixels and the left-eye pixels are output from the active matrixsubstrate. Alternatively, circularly polarized light may be output. Inthis case, the phase layer should be disposed on the surface of thepolarizing layers closer to the light-incident side of the active matrixsubstrate, not on the surface of the polarizing layers farther from thelight-incident side as in Examples 1 and 2. More specifically, the phaselayer composed of the regions corresponding to the right-eye pixels(hereinbelow, referred to as the right-eye regions) and the regionscorresponding to the left-eye pixels (hereinafter, referred to as theleft-eye regions) is disposed on the surface of the polarizing layerscloser to the light-incident side so that the right-eye regionscorrespond to the polarizing layers for the right eye and the left-eyeregions correspond to the polarizing layers for the left eye. At thistime, a slow axis of the right-eye regions of the phase layer isarranged to be inclined by 45° in a predetermined direction with respectto the polarizing axis of the polarizing layers for the right eye.Likewise, a slow axis of the left-eye regions of the phase layer isarranged to be inclined by 45° in a direction opposite to the abovepredetermined direction with respect to the polarizing axis of thepolarizing layers for the left eye. The phase layer therefore has theslow axes of the same direction in the right-eye and left-eye regions.The phase difference between the right-eye and left-eye regions isadjusted to be a 1/4 wavelength.

In the reflective liquid crystal display device with the aboveconfiguration, two types of linearly polarized light of which polarizingdirections are perpendicular to each other are output from thepolarizing layers for the right and left eyes after being reflected bythe light reflection layer disposed on the transparent insulatingsubstrate of the counter substrate and passing through the liquidcrystal layer. Such light enters the phase layer and is converted intotwo types of circularly polarized light of which rotational directionsare opposite to each other by the right-eye and left-eye regions of thephase layer. In this way, for example, clockwise circularly polarizedlight is output from the right-eye regions and counterclockwisecircularly polarized light is output from the left-eye regions. Theobserver who wears a pair of polarizing glasses having circularpolarizing plates corresponding to the polarizing states of theright-eye and left-eye regions receives only right-eye images in theright eye and only left-eye images in the left eye. In this case, evenif the observer moves his or her head upward or downward or tilts thehead, his or her right and left eyes receive right-eye and left-eyeimages correctly. This eliminates the occurrence of crosstalk causingimage doubling, and thus the observer can perceive three-dimensionalimages with higher display quality.

The reflective liquid crystal display device according to the presentinvention is not restricted to the direct-view display by portableinformation terminals, but can also be used for the projection displayby projectors, OHPs, and the like. However, the reflective liquidcrystal display device according to the present invention isparticularly advantageous when used as a display of a portableinformation terminal, for example, in that the confidentiality ofdisplayed information can be enhanced. This is because, whenconfidential information is displayed as three-dimensional images, suchinformation cannot be observed by anyone other than an wearer of thepair of polarizing glasses. The displayed three-dimensional images areonly observed as doubling blurred images by viewers who do not wear thepair of polarizing glasses.

As described above, the present invention eliminates the generation ofcrosstalk at the display of three-dimensional images by providing theinterlayer insulating film with the polarization selection function.This makes it possible to obtain images with a wide viewing angle andthus to improve the display quality. Since the interlayer insulatingfilm is provided with the polarization selection function, thefabrication process as well as the fabrication cost can be reducedcompared with the case where polarizing layers are separately formed.

According to the present invention, three-dimensional image display isrealized by a reflective liquid crystal display device by forming alight reflection layer in the counter substrate of the liquid crystaldisplay device. Therefore, a light source for illumination is notrequired. This provides a thin and lightweight liquid crystal displaydevice with low power consumption, and thereby expands the field forwhich the three-dimensional image display device is applicable.

In the liquid crystal display device according to the present invention,the interlayer insulating film is constructed of a plurality of regionshaving the polarization selection function composed of at least onepixel. These regions are arranged so that the directions of thepolarizing axes of any adjacent regions are different from each other.

The liquid crystal display device according to the present invention mayalso be used for a reflective three-dimensional projector. The liquidcrystal display device according to the present invention is thereforeusable for both direct-view display and projection display. For thedirect-view display, the active matrix substrate is positioned to facethe observer. For the projection display, the active matrix substrate ispositioned to be closer to the light source. This further expands thefield for which the liquid crystal display device having thethree-dimensional display function is applicable.

Circularly polarized light may be output from the liquid crystal displaydevice by forming the phase layer having the phase difference providingfunction on the surface of the polarizing layer having the polarizationselection function as the interlayer insulating film closer to thelight-incident side. This eliminates the generation of crosstalk evenwhen the observer tilts his or her head, and thus further enhances thedisplay quality of three-dimensional images.

Only the wearer of the pair of polarizing glasses can perceivethree-dimensional images generated by the reflective liquid crystaldisplay device according to the present invention. This is thereforesuitable for the display of images corresponding to confidentialinformation.

EXAMPLE 3

In Example 3, reflective pixel electrodes are provided in the activematrix substrate, at least the phase layer among the polarizing layersand the phase layer is provided in the inner surface portion of thecounter substrate, and two types of light with different polarizingstates corresponding to right-eye pixels and left-eye pixels are outputfrom the side of the counter substrate, so as to display images. Thepixels of the liquid crystal display device of this example are dividedinto a plurality of groups each composed of at least one pixel. Pixelsin the same group are used to display the same image.

FIG. 6 is a sectional view schematically showing a reflective liquidcrystal display device 300 of Example 3 according to the presentinvention.

The reflective liquid crystal display device 300 includes an activematrix substrate 301, a counter substrate 302, and a liquid crystallayer 21 interposed between the substrates 301 and 302. The activematrix substrate 301 includes a transparent insulating substrate 22.TFTs 23 as switching elements are formed in a matrix on the surface ofthe transparent insulating substrate 22 facing the liquid crystal layer21. An interlayer insulating film 24 is formed on the resultantsubstrate. Reflective pixel electrodes 25 made of a metal material suchas Al or Ag, for example, are formed in a matrix on the interlayerinsulating film 24, and connected with the respective TFTs 23 viathrough holes formed through the interlayer insulating film 24. Analignment film 20 is formed on the resultant substrate. The alignmentfilm 20 is alignment-treated so that liquid crystal molecules in contactwith the alignment film 20 are aligned in a same direction over theentire display screen.

FIG. 7 shows the portion of the active matrix substrate 301corresponding to one pixel in more detail.

Gate electrodes 26 and gate signal lines (not shown) connected therewithmade of Ta or Al, for example, are formed on the transparent insulatingsubstrate 22. A gate insulating film 27 made of SiN or SiO₂, forexample, is formed over the gate electrodes 26 and the gate signallines. Semiconductor layers 28 of the TFTs 23 are formed on the portionsof the gate insulating film 27 located above the gate electrodes 26.Contact layers 29 and 31 for source electrodes 30 and drain electrodes32, respectively, are formed on the semiconductor layers 28 with a spacetherebetween. For example, amorphous silicon (a-Si) is used for thesemiconductor layers 28, and n⁺ -Si is used for the contact layers 29and 31. The source electrodes 30 are connected to source signal lines(not shown). Thus, the TFTs 23 are completed.

The interlayer insulating film 24 is formed over the entire surface ofthe transparent insulating substrate 22 covering the TFTs 23. Aphotosensitive organic material such as a photosensitive acrylic resin,for example, may be used for the interlayer insulating film 24. Thethrough holes are formed through the interlayer insulating film 24 atpositions corresponding to the drain electrodes 32. The pixel electrodes25 made of Al or Ag, for example, are formed in a matrix on theinterlayer insulating film 24 so that they are connected with the drainelectrodes 32 of the corresponding TFTs 23 through the through holes.The alignment film 20 made of polyimide, for example, is formed over thepixel electrodes 25 and alignment-treated. Thus, the active matrixsubstrate 301 is completed. The alignment film 20 is alignment-treatedso that liquid crystal molecules in contact with the alignment film 20are aligned in the same direction over the entire display screen.

The configuration of the counter substrate 302 is now described withreference to FIG. 6. Color filters 13 are formed on the inner surface ofa transparent insulating substrate 11 facing the liquid crystal layer21. The color filters 13 may be made of red (R), green (G), and blue (B)pixels, or made of cyan (C), magenta (M), and yellow (Y) pixels, inconsideration of the image display by the reflective display device anddepending on the field where the display device is applied. Polarizinglayers 14 and 15 and a phase layer 18 are formed on the color filters13.

The polarizing layers 14 and 15 have polarizing axis 14a and 15a,respectively, which are perpendicular to each other, and are disposed sothat one of each pair of the polarizing layers 14 or 15 corresponds to aright-eye pixel group while the other one corresponds to a left-eyepixel group. In this example, each pixel group is composed of one row ofpixels aligned in the horizontal direction (i.e., pixels sharing a samegate signal line). These pixel groups are allocated for the right eyeand the left eye every row of pixels. The polarizing layers 14 and 15are therefore alternately disposed every row of pixels (i.e, in a shapeof horizontal stripes). The phase layer 18 is composed of regions 16which do not provide a phase difference to incident light and regions 17which provide a phase difference to incident light. The regions 16 and17 are arranged to correspond to the polarizing layers 14 and 15,respectively. Thus, the regions 16 and 17 are also alternately formedevery row of pixels. The regions 17 having the phase differenceproviding function have a slow axis shifted by 45° with respect to thepolarizing axis 15a of the corresponding polarizing layers 15, therebyproviding a phase difference of a half wavelength. By arranging thepolarizing layers 14 and 15 and the regions 16 and 17 of the phase layer18 in the shape of horizontal stripes, the resolution in the horizontaldirection is not degraded, though the resolution in the verticaldirection lowers to a half. This apparently reduces the lowering of theresolution of the three-dimensional images perceived.

A transparent electrode 19 as the counter electrode and an alignmentfilm 20 alignment-treated in a same direction over the entire surfaceare formed in this order on the phase layer 18. A reflection blockinglayer 12 for blocking the reflection of ambient light may be disposed onthe outer surface of the transparent insulating substrate 11 of thecounter substrate 302, as required.

The polarizing layers 14 and 15 of the counter substrate 302 are made ofa mixture of a photo-oriented organic material and a dichromatic pigmentdye or iodide. This material is applied to the resultant surface of thetransparent insulating substrate 11 to a predetermined thickness. Theapplied material is then irradiated with ultraviolet (UV) lightincluding linearly polarized light via a mask disposed on the appliedmaterial. The mask has open portions each corresponding to one row ofpixels and light-shading portions each corresponding to one row ofpixels alternately arranged. The UV light passes through the openportions of the mask to form the polarizing layers in which thepolarizing axis is along the polarizing direction of the UV light. Then,the mask is rearranged so that the open portions thereof are locatedabove the portions of the applied material which have not previouslybeen irradiated with the UV light, and is irradiated with UV lightincluding linearly polarized light which polarizes in a directiondifferent from that of the previously-used UV light by 90°. In this way,the polarizing layers in which the polarizing axes are different fromeach other by 90° are formed alternately in every row of pixels. Apolymer material which exhibits a photoisomerization reaction (e.g., apolymer including azobenzene as a side chain) as disclosed in JapaneseLaid-Open Publication No. 7-261024 and a dichromatic pigment may be usedfor the polarizing layers.

The phase layer 18 is formed in substantially the same procedure as thepolarizing layers 14 and 15. That is, a photopolymerizable liquidcrystal material, for example, is applied to the polarizing layers 14and 15 to a predetermined thickness. The applied material is irradiatedwith UV light including linearly polarized light via a mask which hasopen portions each corresponding to one row of pixels and light-shadingportions each corresponding to one row of pixels alternately arranged.The mask is disposed on the applied material so that the open portionscorrespond to the portions of the applied material which are to be theregions 17 having the phase difference providing function. Thus, theregions 17 which have an optical axis along the polarizing direction ofthe incident UV light and provide a phase difference of a halfwavelength are formed. A UV-curable liquid crystal material exhibitingthe nematic phase at room temperature as disclosed in Japanese Laid-OpenPublication No. 8-29618 may be used for the phase layer.

The liquid crystal layer 21 is made of a guest-host mode liquid crystalmaterial. In this example, a mixture of a p-type black pigment as adichromatic pigment and a nematic liquid crystal material having apositive dielectric anisotropy is used. The liquid crystal molecules andthe dichromatic pigment molecules are aligned so that the opticalabsorption axis of the dichromatic pigment molecules obtained when theliquid crystal molecules and the dichromatic pigment molecules have beenaligned is parallel to the polarizing direction of light which haspassed through the polarizing layers and the phase layer. With thisalignment, polarized light incident on the liquid crystal layer 21 isabsorbed by the dichromatic pigment molecules when the TFTs 23 are inthe OFF state, i.e., when no electric field is applied to the liquidcrystal layer 21, resulting in black display. When the TFTs 23 are inthe ON state, i.e., when an electric field is applied to the liquidcrystal layer 21, the orientation directions of the liquid crystalmolecules and the dichromatic pigment molecules change depending on theelectric field. Polarized light incident on the liquid crystal layer 21therefore passes through the liquid crystal layer 21 without beingabsorbed by the dichromatic pigment molecules.

In the reflective liquid crystal display device 300 with the aboveconfiguration, ambient light is incident on the counter substrate 302,and converted into two types of linearly polarized light of whichpolarizing axes are perpendicular to each other by passing through thepolarizing layers 14 and 15 formed alternately every row of pixels. Thetwo types of light then pass through the phase layer 18, where thepolarizing direction of one of the two types of linearly polarized lightis made the same as that of the other type of linearly polarized light.The resultant two types of light enter the liquid crystal layer 21.Accordingly, the amount of light passing through the liquid crystallayer 21 can be adjusted for the entire screen by controlling the liquidcrystal layer 21.

More specifically, when the TFTs 23 are in the OFF state, light isabsorbed and thus black display is obtained. On the contrary, when theTFTs 23 are in the ON state, light passes through the liquid crystallayer 21, and is reflected by the reflective pixel electrodes 25 to beincident on the phase layer 18 again via the reverse optical path whilethe polarizing directions of the light being held. The light which isincident on the regions 17 of the phase layer 18 having the phasedifference providing function is provided with a phase difference of ahalf wavelength, and becomes light in which the polarizing direction hasbeen rotated by 90°. Accordingly, two types of linearly polarized lightof which polarizing directions are perpendicular to each other areoutput from the phase layer 18 alternately every row of pixels. Thepolarizing layers 14 and 15 receive these two types of linearlypolarized light which are polarized in the directions identical to thedirections of their own polarizing axes. As a result, lightcorresponding to the right-eye images and light corresponding to theleft-eye images are output from the counter substrate 302 as two typesof linearly polarized light which are polarized in the directionsperpendicular to each other.

As described above, the reflective liquid crystal display device 300 ofExample 3 also outputs two types of light for right-eye images andleft-eye images alternately every row of pixels. In the reflectiveliquid crystal display device 300 with the above configuration, theobserver can perceive three-dimensional images from the side of thecounter substrate 302 by wearing a pair of polarizing glasses (notshown) which include polarizing plates having the polarizing axescorresponding to the polarizing axes of the polarizing layers 14 and 15.The liquid crystal display device 300 of Example 3 which is of areflective type using ambient light requires no light source forillumination (backlight). This provides a liquid crystal display devicewith low power consumption, and thereby expands the field for which thethree-dimensional image display device is applicable.

The reflective liquid crystal display device 300 of Example 3 can alsobe used to display normal two-dimensional images by applying imagesignals to pixels in a known manner. In this case, of course, theobserver is not required to wear a pair of polarizing glasses.

In the reflective liquid crystal display device 300 of Example 3, thepixel electrodes formed inside the display device, i.e., in the innersurface portion of the active matrix substrate 301, are used as thelight reflection layer. This eliminates the generation of blur of pixeloutlines caused by the thickness of the transparent insulating substrate22, and thus good display quality can be obtained.

In this example, the switching elements for driving pixels are providedfor all pixels. The present invention is also applicable to other typesof display modes such as a twisted nematic mode. When the guest-hostdisplay mode is employed, a high voltage ON/OFF ratio is required at thedriving of liquid crystal to obtain a high contrast ratio. In Example 3,the voltage ON/OFF ratio at the driving of liquid crystal can be madehigh by providing the switching elements in the substrate. As a result,a high contrast ratio and thus improved display quality can be obtained.

EXAMPLE 4

A reflective liquid crystal display device of Example 4 will bedescribed with reference to FIG. 8.

FIG. 8 is a sectional view schematically showing a reflective liquidcrystal display device 400 of Example 4 according to the presentinvention. In Figure 8, the same components as those shown in FIGS. 6and 7 are denoted by the same reference numerals, and the descriptionthereof is omitted here.

The reflective liquid crystal display device 400 includes an activematrix substrate 401, a counter substrate 402, and a liquid crystallayer 21 interposed between the substrates 401 and 402. Theconfiguration of the active matrix substrate 401 is the same as that inExample 3, except that an alignment film 420 is different from thealignment film 20 in Example 3. The alignment film 420 is composed ofregions 420a and 420b which have been alignment-treated differently fromeach other so that the regions 420a correspond to right-eye pixels andthe regions 420b correspond to left-eye pixels. As in Example 3, rows ofpixels aligned in the horizontal direction are alternately allocated forthe right eye and the left eye every row of pixels. Thus, the regions420a and 420b of the alignment film 420 are also arranged alternatelyevery row of pixels. The regions 420a and 420b of the alignment film 420are alignment-treated so that the orientation directions of liquidcrystal molecules in contact with the regions 420a and 420b areperpendicular to each other.

The configuration of the counter substrate 402 in Example 4 is the sameas that in Example 3, except that the phase layer is omitted in Example4 and that an alignment film 420' in Example 4 is different from thealignment film 20 in Example 3. As the alignment film 420 of the activematrix substrate 401, the alignment film 420' is composed of regions420a' and 420b' corresponding to right-eye pixels and left-eye pixels,respectively. The regions 420a' and 420b' of the alignment film 420'have been alignment-treated differently from each other so that theorientation directions of liquid crystal molecules in contact with theregions 420a' and 420b' are perpendicular to each other, and arrangedalternately every row of pixels. Thus, the regions 420a' of thealignment film 420' correspond to the regions 420a of the alignment film420, while the regions 420b' of the alignment film 420' correspond tothe regions 420b of the alignment film 420. The alignment directions ofthe regions of the alignment films 420 and 420' are determined so thatthe opposing regions 420a and 420a' (or 420b and 420b') regulate theorientation direction of liquid crystal molecules 21a (or 21b) in theliquid crystal layer 21 interposed between these regions in a samedirection.

The liquid crystal layer 21 is made of a guest-host mode liquid crystalmaterial as in Example 3. In this example, a mixture of a p-type blackpigment as a dichromatic pigment and a nematic liquid crystal materialhaving a positive dielectric anisotropy is used. The orientationdirection of the liquid crystal molecules 21a interposed between theregions 420a of the alignment film 420 and the regions 420a' of thealignment film 420' is perpendicular to the orientation direction of theliquid crystal molecules 21b interposed between the regions 420b of thealignment film 420 and the regions 420b' of the alignment film 420'. Forthe entire display screen, the regions of the liquid crystal layer 21having the orientation directions perpendicular to each other arealternately formed every row of pixels. In this way, the polarizingdirection of light incident on the liquid crystal layer 21 after passingthrough the polarizing layers 14 and 15 of the counter substrate 402 canbe made in parallel with the absorption axis of the dichromatic pigmentmolecules in the liquid crystal layer 21 obtained when no electric fieldis applied to the liquid crystal layer 21.

The light orientation method was used as an alignment treatment methodfor the alignment films 420 and 420'. That is, an alignment materialsuch as a photosensitive resin, e.g., polyvinyl cinnamate, is applied tothe resultant surfaces of the transparent insulating substrate 22 of theactive matrix substrate 401 and the transparent insulating substrate 11of the counter substrate 402 to a predetermined thickness. The appliedmaterial of each of the substrates 401 and 402 is irradiated withultraviolet (UV) light including linearly polarized light in verticaland inclined directions via a mask disposed on the applied material. Themask has open portions and light-shading portions alternately arrangedto correspond to every row of pixels. In this way, the regions 420a,420b, 420a', and 420b' having alignment directions along the polarizingdirections of the irradiated light are formed.

In the reflective liquid crystal display device 400 with the aboveconfiguration, ambient light incident on the counter substrate 402 isconverted into two types of linearly polarized light of which polarizingdirections are perpendicular to each other after passing through thepolarizing layers 14 and 15 formed alternately every row of pixels. Thelinearly polarized light then passes through the alignment film 420' tobe incident on the liquid crystal layer 21. Since the orientationdirections of the liquid crystal molecules in the liquid crystal layer21 are perpendicular to each other every row of pixels so as tocorrespond to the polarizing axes of the polarizing layers 14 and 15,the amount of light passing through the liquid crystal layer 21 can beadjusted over the entire screen by adjusting the orientation directionsof the liquid crystal molecules and the dichromatic pigment molecules.More specifically, when the TFTs are in the OFF state, light is absorbedand thus a black display is obtained. On the contrary, when the TFTs arein the ON state, light passes through the liquid crystal layer 21 and isreflected by the reflective pixel electrodes 25.

The light reflected by the reflective pixel electrode 25 is incident onthe polarizing layers 14 and 15 again via the reverse optical path whilethe polarizing directions of the light are held. Thus, the polarizinglayers 14 and 15 receive the types of light of which polarizingdirections are identical to the directions of their own polarizing axes.The polarizing layers 14 and 15 therefore allow the incident light topass therethrough, and the light is output from the counter substrate402. In this way, light corresponding to the right-eye images and lightcorresponding to the left-eye images are output as two types of linearlypolarized light which are polarized in the directions perpendicular toeach other.

In the reflective liquid crystal display device 400 with the aboveconfiguration, the observer can perceive three-dimensional images outputfrom the side of the counter substrate 402 by wearing a pair ofpolarizing glasses (not shown) which include polarizing plates havingthe polarizing axes corresponding to the polarizing axes of thepolarizing layers 14 and 15. The reflective liquid crystal displaydevice 400 of Example 4 can also be used to display normaltwo-dimensional images by applying image signals to pixels in a knownmanner. In this case, of course, the observer is not required to wear apair of polarizing glasses.

The liquid crystal display device 400 of Example 4 which is of areflective type using ambient light requires no light source forillumination (backlight). This provides a liquid crystal display devicewith low power consumption, and thereby expands the field for which thethree-dimensional image display device is applicable. Moreover, thepixel electrodes 25 formed in the inner surface portion of the activematrix substrate 401 are used as the light reflection layer. Thiseliminates the generation of blur of pixel outlines caused by thethickness of the transparent insulating substrate 22, and thus gooddisplay quality can be obtained.

In Example 4, two types of linearly polarized light of which polarizingdirections are different from each other for the right-eye pixels andthe left-eye pixels are output from the counter substrate.Alternatively, circularly polarized light may be output. In this case,as shown in FIG. 15, a phase layer 418 which serves as a filter ofcircularly polarized light is disposed on the surface of the polarizinglayers 14 and 15 closer to the light-incident side of a countersubstrate 402' (i.e., closer to the transparent insulating substrate11).

More specifically, the phase layer 418 composed of right-eye regions andleft-eye regions is disposed on the surface of the polarizing layerscloser to the light-incident side so that the right-eye regionscorrespond to the polarizing layers 14 for the right eye and theleft-eye regions correspond to the polarizing layers 15 for the lefteye. At this time, a slow axis of the right-eye regions of the phaselayer 418 is arranged to be inclined by 45° with respect to thepolarizing axis 14a of the polarizing layers 14 in a predetermineddirection. Likewise, a slow axis of the left-eye regions of the phaselayer 418 is arranged to be inclined by 45° with respect to thepolarizing axis 15a of the polarizing layers 15 in a direction oppositeto the above predetermined direction. The phase layer 418 therefore hasthe slow axes of the same direction in the right-eye and left-eyeregions. The phase difference between the right-eye and left-eye regionsis adjusted to be a 1/4 wavelength.

In the reflective liquid crystal display device with the aboveconfiguration, two types of linearly polarized light of which polarizingdirections are perpendicular to each other are output from thepolarizing layers 14 and 15 for the right and left eyes after beingreflected by the reflective pixel electrodes 25 and passing through theliquid crystal layer 21. Such light enters the phase layer 418 and isconverted into two types of circularly polarized light of whichrotational directions are opposite to each other by the right-eye andleft-eye regions of the phase layer 418. In this way, for example,clockwise circularly polarized light is output from the right-eyeregions and counterclockwise circularly polarized light is output fromthe left-eye regions. The observer who wears a glass of polarizingglasses having circularly polarizing plates corresponding to thepolarizing states of the right-eye and left-eye regions receives onlyright-eye images in the right eye and only left-eye images in the lefteye. In this case, even if the observer moves his or her head upward ordownward or tilts the head, his or her right and left eyes receivelight-eye and left-eye images correctly. This eliminates the generationof crosstalk causing image doubling, and thus the observer can perceivethree-dimensional images with higher display quality.

In Example 4, the guest-host display mode was employed. The presentinvention is also applicable to other types of display modes such as thetwisted nematic mode.

EXAMPLE 5

A reflective liquid crystal display device of Example 5 will bedescribed with reference to FIGS. 9 to 11. In FIGS. 9 to 11A and 11B,the same components as those shown in FIGS. 6 to 8 are denoted by thesame reference numerals, and the description thereof is omitted here.

FIG. 9 is a sectional view schematically showing a reflective liquidcrystal display device 500 of Example 5 according to the presentinvention.

The reflective liquid crystal display device 500 includes an activematrix substrate 501, a counter substrate 502, and a liquid crystallayer 521 interposed between the substrates 501 and 502. Theconfiguration of the active matrix substrate 501 is the same as that inExample 3, except that an alignment film 520 is different from thealignment film 20 in Example 3. As in Example 4, the alignment film 520is composed of regions 520a and 520b which have been alignment-treateddifferently from each other so that the regions 520a correspond toright-eye pixels and the regions 520b correspond to left-eye pixels. Asin the previous examples, rows of pixels aligned in the horizontaldirection are alternately allocated for the right eye and the left eyeevery row of pixels. Thus, the regions 520a and 520b of the alignmentfilm 520 are also arranged alternately every row of pixels. The regions520a and 520b of the alignment film 520 are alignment-treated so thatthe orientation directions of liquid crystal molecules in contact withthe regions 520a and 520b are perpendicular to each other.

The counter substrate 502 includes a transparent insulating substrate11. Color filters 13, polarizing layers 14 and 15, a phase layer 518, acounter electrode 19, and an alignment film 520' are formed in thisorder on the inner surface of the transparent insulating substrate 11facing the liquid crystal layer 521. A reflection blocking layer 12 forblocking the reflection of ambient light may be disposed on the outersurface of the transparent insulating substrate 11 of the countersubstrate 502, as required.

The color filters 13 may be made of red (R), green (G), and blue (B)pixels, or made of cyan (C), magenta (M), and yellow (Y) pixels, inconsideration of the image display by the reflective display device anddepending on the field where the reflective liquid crystal displaydevice 500 is applied.

The polarizing layers 14 and 15 have the polarizing axes 14a and 15aperpendicular to each other, and are alternately disposed every row ofpixels (i.e, in the shape of horizontal stripes) so that the polarizinglayers 14 correspond to right-eye pixels and the polarizing layers 15correspond to left-eye pixels, as in Example 3. The polarizing layers 14and 15 are formed in the manner described in Example 3.

The phase layer 518 is composed of regions 516 and 517 having slow axesperpendicular to each other. The phase layer 518 is formed in the mannerdescribed in Example 3. As shown in FIG. 9, the regions 516 and 517 arearranged to correspond to the polarizing layers 14 and 15, respectively,and thus arranged alternately every row of pixels. The slow axis of theregions 516 is rotated by 45° clockwise with respect to the polarizingaxis 14a of the polarizing layers 14. Likewise, the slow axis of theregions 517 is rotated by 45° clockwise with respect to the polarizingaxis 15a of the polarizing layers 15.

A transparent electrode 19 as the counter electrode and an alignmentfilm 520' are formed on the phase layer 518. The alignment film 520' iscomposed of regions 520a' and 520b' which are alignment-treateddifferently so that liquid crystal molecules in contact with theseregions are aligned in directions different from each other. As shown inFIG. 9, the regions 520a' and 520b' are also arranged alternately everyrow of pixels to correspond to the regions 520a and 520b of thealignment film 520 of the active matrix substrate 501, respectively. Theregions 520a' are alignment-treated so that the liquid crystal moleculesin contact therewith are aligned in a direction rotated by 45°counterclockwise with respect to the polarizing axis 14a of thecorresponding polarizing layers 14. Likewise, the regions 520b' arealignment-treated so that the liquid crystal molecules in contacttherewith are aligned in a direction rotated by 45° counterclockwisewith respect to the polarizing axis 15a of the corresponding polarizinglayers 15. The opposing regions of the alignment films 520 and 520' aretreated so that the liquid crystal molecules interposed therebetween arealigned in the same direction.

FIG. 10 shows an optical configuration of the reflective liquid crystaldisplay device 500. An axial direction L2 of the slow axis of theregions 516 (or 517) of the phase layer 518 is set at an angle θ1clockwise with respect to an axial direction L1 of the polarizing axis14a (or 15a) of the corresponding polarizing layer 14 (or 15). Anorientation direction L3 of liquid crystal molecules 521a (or 521b) inthe corresponding regions is set at an angle θ2 counterclockwise withrespect to the axial direction L1. In this example, both angles θ1 andθ2 are 45°.

The photo-orientation method is employed for the alignment treatment ofthe alignment films 520 and 520', as in Example 4. Specifically, aphotosensitive resin, e.g., polyvinyl cinnamate, is applied to theresultant surfaces of the transparent insulating substrate 22 of theactive matrix substrate 501 and the transparent insulating substrate 11of the counter substrate 502 to a predetermined thickness. The appliedmaterial of each of the substrates 501 and 502 is irradiated withultraviolet (UV) light including linearly polarized light in verticaland inclined directions via a mask disposed on the applied material. Themask has open portions and light-shading portions alternately arrangedto correspond to every row of pixels. In this way, the regions 520a,520b, 520a', and 520b' having alignment directions along the polarizingdirections of the irradiated light are formed.

A material of an electric field control birefringence (ECB) mode may beused for the liquid crystal layer 521. In this example, as a liquidcrystal material with a positive dielectric anisotropy, ZLI4792 (Merck &Co., Inc.) with a refractive index anisotropy Δn1 of 0.094 is used, toform the liquid crystal layer 521 with a thickness d1 of 5.5 μm.Therefore, a retardation Δn1·d1 of the liquid crystal layer 521 is 517nm. In correspondence with this retardation, a retardation Δn2·d21 ofthe phase layer 518 (with an optical anisotropy Δn2 and a thickness d2)is set to satisfy (Δn1·d-Δn2·d2)/λ=0.25 when light with a wavelength λof 550 nm is incident on the phase layer 518. Specifically, Δn2·d2 isset at 380 nm. With this setting, a black display is obtained when theTFTs 23 are in the OFF state, in which polarized light reflected by thereflective pixel electrodes 25 of the active matrix substrate 501 isblocked from passing through the polarizing layers 14 and 15. On thecontrary, a white display is obtained when the TFTs 23 are in the ONstate, in which polarized light reflected by the reflective pixelelectrodes 25 is allowed to pass through the polarizing layers 14 and15. The setting of the value of (Δn1·d1·Δn2·d2)λ is not limited to theabove value, but any setting is possible as far as monochromatic displayis achieved.

FIGS. 11A and 11B illustrate the operational principle of the reflectiveliquid crystal display device 500 of Example 5. In FIGS. 11A and 11B,the liquid crystal display device 500 is exploded to facilitate thedescription of the operational principle.

FIG. 11A shows the state in which reflected light is blocked. Incidentlight 10 which has passed through the polarizing layer 14 is convertedinto linearly polarized light 61 having a polarizing direction parallelto the direction L1 of the polarizing axis of the polarizing layer 14.The linearly polarized light 61 then passes through the region 516 ofthe phase layer 518 and the liquid crystal layer 521 to be output asclockwise circularly polarized light 63, for example. The circularlypolarized light 63 is reflected by the reflective pixel electrode 25 andconverted into counterclockwise circularly polarized light 64. Thecircularly polarized light 64 passes back through the liquid crystallayer 521 and the region 516 of the phase layer 518 having therespective retardations described above, to be output as linearlypolarized light 62 having a polarizing direction perpendicular to thepolarizing direction of the linearly polarized light 61. The linearlypolarized light 62 is therefore blocked from passing through thepolarizing layer 14. Thus, a black display is obtained. In the casewhere the light incident on the reflective pixel electrode 25 afterpassing through the liquid crystal layer 521 is counterclockwisecircularly polarized light, the light reflected from the reflectivepixel electrode 25 is clockwise polarized light.

FIG. 11B shows the state in which reflected light is transmitted. Whenthe TFT 23 is turned into the ON state to allow a voltage to be appliedto the liquid crystal layer 521, the orientation of the liquid crystalmolecule 521a is changed to satisfy the relationship between theretardations of the phase layer 518 and the liquid crystal layer 521,(Δn1·d1-Δn2·d2)λ=0±0.1. Under this state, the linearly polarized light61 having the polarizing direction parallel to the polarizing axis 14aof the polarizing layer 14 is allowed to pass through the region 516 ofthe phase layer 518 and the liquid crystal layer 521 while holding thepolarizing state. The polarizing state of the linearly polarized light61 is also held when it is reflected by the reflective pixel electrode25 and when it passes back through the liquid crystal layer 521 and theregion 516 of the phase layer 518. The reflected light with thispolarizing state is allowed to pass through the polarizing layer 14 tobe output from the device. Thus, a white display is obtained.

As described above, in the reflective liquid crystal display device 500,light corresponding to the right-eye images and light corresponding tothe left-eye images are output from the side of the counter substrate502 as two types of linearly polarized light which are polarized in thedirections perpendicular to each other. Accordingly, the observer canperceive three-dimensional images from the side of the counter substrate502 by wearing a pair of polarizing glasses (not shown) which includepolarizing plates having the polarizing axes corresponding to thepolarizing axes of the polarizing layers 14 and 15. When the observerdoes not wear the pair of polarizing glasses, the observer observestwo-dimensional images.

In Example 5, since the ECB display mode is employed, gray-scale displayis also possible.

The liquid crystal display device 500 of Example 5 which is of areflective type using ambient light requires no light source forillumination (backlight). This provides a liquid crystal display devicewith low power consumption, and thereby expands the field for which thethree-dimensional image display device is applicable. Moreover, sincethe polarizing layers and the phase layer are formed in the innersurface portion of the counter substrate 502, the generation ofcrosstalk caused by the thickness of the transparent insulatingsubstrate 11 is eliminated, and thus good display quality can beobtained. Furthermore, since the switching elements are provided, thevoltage ON/OFF ratio at the driving of liquid crystal can be made high.As a result, a high contrast and thus improved display quality can beobtained.

The liquid crystal display device which includes the phase layer havingthe phase difference providing function can employ a wider range ofdisplay modes. For example, the reflective liquid crystal display device500 of Example 5 may employ the guest-host mode or the twisted nematicmode, in place of the ECB mode. The configuration of the components ofthe liquid crystal display device 500 may be changed depending on thedisplay mode employed.

EXAMPLE 6

A reflective liquid crystal display device of Example 6 will bedescribed with reference to FIG. 12. In FIG. 12, the same components asthose shown in FIGS. 6 to 11A and 11B are denoted by the same referencenumerals, and the description thereof is omitted here.

FIG. 12 is a sectional view schematically showing a reflective liquidcrystal display device 600 of Example 6 according to the presentinvention.

The reflective liquid crystal display device 600 includes an activematrix substrate 601, a counter substrate 602, and a liquid crystallayer 621 interposed between the substrates 601 and 602. Theconfiguration of the active matrix substrate 601 is the same as that inExample 3. The alignment film 20 is alignment-treated so that liquidcrystal molecules in contact with the alignment film 20 are oriented inthe same direction over the entire display screen.

The configuration of the counter substrate 602 in Example 6 is the sameas the counter substrate 102 in Example 3, except that an additionalphase layer 618 is provided between the phase layer 18 and the counterelectrodes 19.

The polarizing layers 14 and 15 have the polarizing axes 14a and 15aperpendicular to each other, and are alternately disposed so that thepolarizing layers 14 correspond to right-eye pixels and the polarizinglayers 15 correspond to left-eye pixels. In Example 6, as in Example 3,rows of pixels aligned in the horizontal direction are alternatelyallocated for the right eye and the left eye every row of pixels. Thus,the polarizing layers 14 and 15 are alternately disposed every row ofpixels (i.e, in the shape of horizontal stripes). The phase layer 18 iscomposed of regions 16 which do not provide a phase difference toincident light and regions 17 which provide a phase difference toincident light. The regions 16 and 17 are arranged alternately every rowof pixels to correspond to the polarizing layers 14 and 15,respectively, as shown in FIG. 12. The regions 17 have a slow axisrotated by 45° with respect to the polarizing axis 15a of thecorresponding polarizing layers 15, thereby providing incident lightwith a phase difference of a half wavelength.

The phase layer 618 is formed on the entire surface of the phase layer18. The slow axis of the phase layer 618 is set to be rotated by 45°clockwise with respect to the polarizing axis 14a of the polarizinglayers 14. The phase layer 618 may be made of a UV-curable liquidcrystal material exhibiting the nematic phase at room temperature asdisclosed in Japanese Laid-Open Publication No. 8-29618.

A transparent electrode 19 as the counter electrode and an alignmentfilm 20 are formed in this order on the phase layer 618. As describedabove, the alignment film 20 is alignment-treated so that the liquidcrystal molecules in contact with the alignment film 20 are aligned inthe same direction. The alignment direction of the alignment film 20 ofthe counter substrate 602 is set so as to be rotated by 45°counterclockwise with respect to the polarizing axis 14a of thecorresponding polarizing layers 14. An alignment film 20 of the activematrix substrate 601 is set in accordance with the twist angle of theliquid crystal layer 621.

An ECB mode material may be used for the liquid crystal layer 621. Inthis example, as a liquid crystal material with a positive dielectricanisotropy, ZLI4792 (Merck & Co., Inc.) with a refractive indexanisotropy Δn1 of 0.094 is used, to form the liquid crystal layer 621with a thickness d1 of 5.5 μm. Therefore, a retardation Δn1·d1 of theliquid crystal layer 621 is 517 nm. In correspondence with thisretardation, a retardation Δn2·d2 of the phase layer 618 (with anoptical anisotropy Δn2 and a thickness d2) is set to satisfy(Δn1·d1-Δn2·d2)/λ=0.5 when light with a wavelength λ of 550 nm isincident on the phase layer 618. Specifically, Δn2·d2 is set at 240 nm.With this setting, a white display is obtained when the TFTs 23 are inthe OFF state, in which polarized light reflected by the reflectivepixel electrodes 25 of the active matrix substrate 601 is allowed topass through the polarizing layers 14 and 15. On the contrary, a blackdisplay is obtained when the TFTs 23 are in the ON state, in whichpolarized light reflected by the reflective pixel electrodes 25 isblocked from passing through the polarizing layers 14 and 15. Thesetting of the value of (Δn1·d1Δn2·d2)/λ. is not limited to the abovevalue, but any setting is possible as far as monochromatic display isachieved.

As described above, in the reflective liquid crystal display device 600of Example 6, light corresponding to the right-eye images and lightcorresponding to the left-eye images are output as two types of linearlypolarized light which are polarized in the directions perpendicular toeach other. Accordingly, the observer can perceive three-dimensionalimages from the side of the counter substrate 602 by wearing a pair ofpolarizing glasses (not shown) which include polarizing plates havingthe polarizing axes corresponding to the polarizing axes of thepolarizing layers 14 and 15. When the observer does not wear the pair ofpolarizing glasses, the observer observes two-dimensional images.

In Example 6, since the ECB display mode is employed, a gray-scaledisplay is also possible. Alternatively, a nematic liquid crystalmaterial twisted by 240° (e.g., SD-4107 manufactured by ChissoCorporation) may be used for the liquid crystal layer to realize thetwisted nematic display mode. In this case, the alignment direction ofthe alignment films 20 is set to correspond to the twist angle 240° ofthe liquid crystal layer. A reflective display mode such as the R-OCBmode which uses polarizing plates may also be employed as the displaymode for the reflective liquid crystal display device 600 of Example 6.

In Examples 3 to 6, each pixel group is composed of one row of pixelsaligned in the horizontal direction. The present invention is notrestricted to this arrangement, but the same effect as that describedabove can also be obtained when each pixel group is composed of onecolumn of pixels aligned in the vertical direction (i.e., pixels sharinga same source signal line). In the latter case, the polarizing layers,the regions of the phase layer and/or the regions of the alignment filmsare also alternately arranged every column of pixels. Alternatively,each pixel group may be composed of only one pixel, and right-eye pixelsand left-eye pixels may be arranged in a checkered flag pattern. Eachpixel group may also be composed of a plurality of rows of pixels or aplurality of columns of pixels. In this case, however, the resolutionlowers compared with the case where each pixel group is composed of onerow of pixels or one column of pixels.

In Examples 3 to 6, the polarizing layers and the phase layer weredisposed inside the liquid crystal display device (in the inner surfaceportion of the counter substrate). Alternatively, at least thepolarizing layers or the phase layer may be disposed in the outersurface portion of the counter substrate. This is also applicable to thelight reflection layer. That is, though the pixel electrodes of theliquid crystal display device were used as the light reflection layer inExamples 3 to 6, the pixel electrodes may be formed as transparentelectrodes and a separate light reflection film may be disposed in theouter surface portion of the liquid crystal display device.

According to the present invention, the configuration of the substratehaving TFTs is not restricted to the configuration described above,i.e., the configuration including the switching elements, the linesconnected to the switching elements, the interlayer insulating filmformed over the switching elements and the lines, and the displayelectrodes formed on the interlayer insulating film. A configurationincluding the switching elements, the lines connected to the switchingelements, and the display electrodes, omitting the interlayer insulatingfilm, may also be used.

As the method for driving the reflective liquid crystal display deviceaccording to the present invention, not only the active matrix drivingmethod using TFTs described in Examples 3 to 6, but also a multiplexdriving method, a multi-line driving method, an active matrix drivingmethod using MIM elements, and the like may be used.

The present invention is not restricted to the configuration ofdisposing the polarizing layers and the phase laser in one of thesubstrates as described above. For example, in the case of thereflective display mode such as the STN mode and the TN mode, twopolarizing plates are used to realize the reflective display mode. Insuch a case, two polarizing layers may be formed on the two substrates,so that light which has passed through the two polarizing layers isreflected by a light reflection layer.

The order of the color filters, the counter electrode, the polarizinglayers, and the phase layer is not restricted to that described inExamples 3 to 6, but may be changed as required.

The reflective liquid crystal display devices for color image displaywere described in Examples 3 to 6. The present invention is alsoapplicable to reflective liquid crystal display devices formonochromatic display.

The reflective liquid crystal display device according to the presentinvention is not restricted to the direct-view display for portableinformation terminals and the like, but can also be used for theprojection display such as projectors and OHPs. However, the reflectiveliquid crystal display device according to the present invention isparticularly advantageous when used as a display of a portableinformation terminal, for example, in that the confidentiality ofdisplayed information can be enhanced. This is because, whenconfidential information is displayed as three-dimensional images, suchinformation cannot be observed by anyone other than the wearer of thepair of polarizing glasses. The displayed three-dimensional images areonly observed as doubling blurred images by viewers who do not wear thepair of polarizing glasses.

Thus, according to the present invention, a light reflection layer isprovided for the liquid crystal display device including the liquidcrystal display elements and the polarizing layers having the polarizingfunction so as to utilize ambient light. A light source for illuminationis therefore unnecessary. This reduces power consumption, and thus aliquid crystal display device for three-dimensional image displaydurable for long-time use can be obtained at low cost.

When the liquid crystal display device includes switching elementsformed in one of the substrates, a high voltage ON/OFF ratio for drivingthe liquid crystal is obtained. This improves the contrast ratio andthus the display quality.

In the reflective liquid crystal display device according to the presentinvention, a plurality of regions each composed of at least one pixeland having a polarization selection function are arranged so that thedirection of the polarizing axes of one region is different from that ofan adjacent region. Especially, each region having the same polarizingdirection extends in the horizontal direction and such regions havingdifferent polarizing directions are alternately arranged in the verticaldirection. With this arrangement, the lowering of the resolution can beapparently reduced when three-dimensional images are perceived.

Moreover, in the reflective liquid crystal display device according tothe present invention, the person who can perceive the three-dimensionalimages is restricted to the wearer of the corresponding pair of glasses.This is therefore suitable for displaying images corresponding toconfidential information.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

What is claimed is:
 1. A liquid crystal display device comprising:aplurality of pixels including right-eye pixels and left-eye pixels; adisplay screen constructed of the plurality of pixels; a first substrateincluding a first display electrode; a second substrate including asecond display electrode arranged opposite the first display electrode;a liquid crystal layer interposed between said first and secondsubstrates; a polarizing layer disposed in at least one of the firstsubstrate and the second substrate; and a reflection film disposed inone of the first substrate and the second substrate, wherein thepolarizing layer has first regions arranged to correspond to theright-eye pixels and second regions arranged to correspond to theleft-eye pixels, the first regions selectively transmitting firstpolarized light and the second regions selectively transmitting secondpolarized light which is different from the first polarized light, andwherein the polarizing layer is disposed in the second substrate, andthe first display electrode is a reflective display electrode which alsoserves as a reflection film.
 2. A liquid crystal display deviceaccording to claim 1, wherein the first polarized light and the secondpolarized light are linearly polarized light of which polarizingdirections are perpendicular to each other.
 3. A liquid crystal displaydevice according to claim 1, wherein the first polarized light and thesecond polarized light are circularly polarized light of whichpolarizing directions are rotated in opposite directions to each other.4. A liquid crystal display device according to claim 3, furthercomprising an optical layer or a phase layer disposed to correspond toat least either of the right-eye pixels and the left-eye pixels.
 5. Aliquid crystal display device according to claim 1, wherein the firstsubstrate further includes switching elements connected to the firstdisplay electrode and signal lines connected to the switching elements.6. A liquid crystal display device according to claim 1, wherein thefirst substrate further includes switching elements connected to thefirst display electrode, signal lines connected to the switchingelements, and an interlayer insulating film formed over the switchingelements and the signal lines, andthe first display electrode is formedon the interlayer insulating film to cover the switching elements.
 7. Aliquid crystal display device according to claim 1, whereinone of anelectric field control birefringence mode, a guest-host mode, and atwisted nematic mode is employed as a display mode.
 8. A liquid crystaldisplay device according to claim 1, further comprising alignment filmsdisposed in the first substrate and the second substrate,wherein thealignment films are alignment-treated so that liquid crystal moleculesin regions of the liquid crystal layer corresponding to the right-eyepixels and liquid crystal molecules in regions of the liquid crystallayer corresponding to the left-eye pixels are oriented in directionsperpendicular to each other.
 9. A liquid crystal display deviceaccording to claim 1, wherein the first substrate includes a firstinsulating plate and the second substrate includes a second insulatingplate, andthe polarizing layer is located between the first insulatingplate and the second insulating plate.